Come valuta cos ((2pi) / 3) cos(2π3)?
Risposta:
-1/2−12
Spiegazione:
The angle (2pi)/3" is in the 2nd quadrant "2π3 is in the 2nd quadrant
where the cos ratio has a negative value.The related 'acute angle' to (2pi)/3 =( pi -(2pi)/3) = pi/3 2π3=(π−2π3)=π3
rArr cos((2pi)/3) = - cos(pi/3) ⇒cos(2π3)=−cos(π3)
and using the color(blue)" Exact value triangle" Exact value triangle
cos((2pi)/3) = - cos(pi/3) = -1/2 cos(2π3)=−cos(π3)=−12